Pivoted axle for motor vehicles



3 Sheets-Sheet l H. PINARD Filed Jan. 12, 1938 PIVOTED AXLE FOR MOTOR VEHICLES Nov. 1, 1938.

Nov. 1, 1938. H. PINARD PIVOTED AXLE FOR MOTOR VEHICLES Filed Jan. 12, 1938 3 Sheets-Sheet 2 INVBMI'U mi a W. *M

S Sheets-Sheet 3 Nov. 1, 1938. H. PINARD PIVOTED AXLE FOR MOTOR VEHICLES Filed Jan. 12, 1938 M w F Nam Patented Nov. 1, 1938 UNITED STATES PATENT OFFICE 10 Claims.

In motor vehicles for oan'ying heavy loads, such as motor trucks for carrying large quantities of merchandise, it has been common practice to provide the vehicle with an auxiliary set of wheels in back of the usual rear wheels to receive part of the load. Vehicles provided with such auxiliary wheels are diificult to steer and produce forces which subject parts of the vehicle to great strain when the vehicle is moving in a curved path. The reason for this is simple. In a vehicle having only the usual front and rear sets of wheels, the rear portion of the vehicle tends to pivot about the point of contact of one of the rear wheels with the ground when the vehicle is traveling in a curved path. This is made possible by the differential which permits one of the rear wheels to rotate at a greater speed than the other. This same action takes place in a vehicle having an auxiliary set of wheels in back of the rear wheels but, since the rear portion of the vehicle cannot pivot simultaneously about two points, the auxiliary set of wheels are dragged laterally of the vehicle when the latter is moved in a curved path. This dragging of the auxiliary wheels opposes any force tending to change the direction of movement of the vehicle from a straight path to a curved path.

My co-pending application, Serial No. 140,108,

filed May 1, 1937, describes a vehicle having a set of auxiliary wheels in back of the rear wheels and which is constructed so as to facilitate steering of the vehicle and to eliminate other objections to previous constructions. This was accomplished by the provision of means permitting the axle of the auxiliary wheels to pivot about a point in front of such axle when the vehicle was moving forward and to pivot about a point in back of such axle when the vehicle was moving rearward. In the construction specifically illustrated in my above mentioned application, manually operable mechanism is provided for shifting a frame for controlling the point about which the axle of the auxiliary wheels could pivot.

My present invention contemplates a construction of the same general character. In accordance with the present invention, however, the point about which the axle of the auxiliary wheels may pivot is controlled by the direction of movement of the vehicle.

These and other features of the invention, will be more clearly understood from the following description in conjunction with the accompanying drawings: in which,

.1 Figs. 1 and 2 are plan views of a motor truck (on. est-97) chassis embodying the invention and showing the parts in different operative positions;

Fig. 3 is a longitudinal sectional view of the same; I

Fig. 4 is a sectional view taken upon the line 5 44 of Fig. 3;

Figs. 5, 6, '7 and 8 are fragmentary plan views of a modified construction showing the parts in different relations; and

Figs. 9 and 10 are sectional views taken on the 10 lines 99 and I0I0 of Figs. 5 and 6, respectively. I

The invention is illustrated in the accompanying drawings as applied to a motor truck chassis which comprises a chassis frame I0 supported 15 upon the usual sets of front wheels II and rear wheels I2. The chassis is supported also by a set of auxiliary wheels I5 positioned in back of the set of rear wheels I2. The front wheels II, rear wheels I2 and auxiliary wheels I5 are provided 20 with brakes I6, I! and I 8, respectively. The brakes may be operated by any brake. operating mechanism and, as illustrated, are operated by a hydraulic system comprising a compression cylinder 20 actuated by the usual brake operat- 25 ing pedal 2|. Fluid pressure conduits 22 and 23 extend forwardly and rearwardly respectively from the compression cylinder 20. The conduit 22 is connected by flexible conduits 24 with the front wheel brakes I6 and the conduit 23 is con- 30 nected by flexible conduits 25 and 26 with the rear wheel brakes I1 and the auxiliary wheel brakes I8, respectively.

The sets of rear wheels I2 and auxiliary wheels I5 form part of a carriage C which is arranged to pivot (as described hereinafter) relative to the other part of the chassis. The carriage C includes two relatively movable frames 21 and 28. The frame 21 comprises a yoke 30 and a platform 3|. connected to the rear vehicle springs 32 by pins 33. The housing 35 for the axle for the rear wheelsv I2 is rigidly secured in anysuitable manner to the ends of the arms of the yoke 30. The platform portion 3| of the frame 21 extends 5 rearwardly from the yoke 30 in a substantially horizontal plane and comprises a pair of spaced longitudinal frame members 36. The ends of the members 36 are connected by transverse frame members 8 and 9, each having a horizon- 50 tal guide slot 31 for the frame 28. Cross members 38 and 39 connect the longitudinal frame members 36 between the transverse members-8 and 9 and are spaced from the latter an amount to provide vertical transversely extending tri- The arms of the yoke 30 arepivotally 40 angularly shaped slots 48 and 4| to permit both longitudinal and transverse movement between the two frames. The cross members 88 and 88 are provided with bearings 42 and 48 respectively communicating with the slots 48 and 4| for a purpose described hereinafter.

The frame 28 comprises a plate 45 extending between and slidably movable in the slots 81 both longitudinally and transversely of the vehicle chassis. The housing 46 for the axle for the auxiliary wheels I! is connected by struts 41 with the plate 45. A pair of pins 58 and ii project upwardly from the top surface of the plate 45 and are spaced apart a greater distance than the bearings 42 and 48. The pin it is adapted to rotatably engage the bearing 48 when the pin ii is free to move transversely in the slot 40 and the pin BI is adapted to rotatably engage the bearing 42 when the pin 88 is free to move transversely in the slot 4!. Separate leaf springs 52 are suitably secured at an intermediate point to each of the longitudinal frame members 88 so that their ends are adapted to engage opposite longitudinal edges of the plate 48 and abut the spaced. enlargements I! and 88 formed thereon to exert a resilient force tending to maintain the pin 5| in the bearing 42 or. the pin 58 in the bearing 48 when these pins have been moved to such positions.

Preferably, the pins 88, which pivotally connect the carriage C to the chassis. are positioned nearer to the axle for the rear wheels l2 than to the axle for the auxiliary wheels 15 so that a greater proportion of the load carried upon .the vehicle chassis is supported by the rear wheels l2 than by the auxiliary wheels i5.

When the vehicle is moving forwardly, the pin 5| will engage the bearing 42 and the pin 58 will be positioned in the slot 4| as is illustrated by the full-line position in Fig. 1. when in this position the frame 28, carrying the set of auxiliary wheels I 5, is free to pivot about the pin 5| as an axis. Consequently, if the vehicle is steered to the left by turning the front wheels II to the dotted-line position as shown in Fig.

1, the frame 28 will pivot about the pin 5! so that the set of auxiliary wheels II will assume the dotted-line position as shown in Fig. 1. If the vehicle is steered so as to return the front wheels II to their full-line position as shown in Fig. 1, to cause the vehicle to move in a straight forward path, the frame 28 will pivot about the pin 5| so as to return the set of auxiliary wheels ii to the full-line position as shown in Fig. 1.

If the vehicle now is stopped and its motion is started in the rearward direction, the plate 45 is shifted from the full-line position, shown in Fig. 1, to the full-line position, shown in Fig. 2, thereby bringing the pin 88 in'engagement with the bearing 48 and positioning the pin Ii in the slot 48. In order to assure the shift of the plate 45 fromthe full-line position shown in Fig. 1 to the full-line position shown in Fig. 2, as the rearward movement of the vehicle is started, the brake pedal 2| may be depressed to ap ply a slight braking pressure upon the vehicle brakes. When this is done the set of auxiliary wheels I I will move rearward at a slower rate than the vehicle inasmuch as a smaller proportion of the vehicle load is supported by the set of auxiliary wheels ll than by the set of rear wheels I2. If the rearward movement of the vehicle continues in a straight path. theset of auxiliary wheels I! will remain'in the full-line position shown in Fig. 2. However, if the steering mechanism of the vehicle is actuated to move the front wheels from the full-line position shown in Fig.2, to the dotted-line position so as to cause the vehicle to move in a curved path, then as the rearward movement of the vehicle 5 continues, the frame 28 will pivot about the pin 43 as an axis to bring the set of auxiliary wheels l5 into the dotted-line position shown in Fig. 2.

It will be understood that if the pin 5! is not in engagement with the bearing 42 or-the pin 10 50 is not in engagement with the bearing 48 when motion of the vehicle is started forward or rearward respectively, they will be moved into such respective positions by the motion of the vehicle either alone or in conjunction with the 15 application of the vehicle brakes. Thus, it will be noted that .regardless of the direction of motion of the vehicle, the frame 28 is always free to pivot about a point in front of the axle for the set of auxiliary wheels I! with respect to the direction of motion. Inasmuch as the set of rear wheels l2 and the set of auxiliary wheels, I! are carried by a carriage which is pivotally connected to the rear vehicle springs, both of these sets of wheels will always be in engagement with the road surface whether passing over a knoll or upon the level. v V

In Fig. 5 there is illustrated the rear portion of a motor truck chassis embodying a modified form of the invention. This modified construction comprises a chassis frame l8 supported upon the usual set of front wheels (not shown) and set of rear driving wheels l2. The chassis is supported also by a set of auxiliary wheels l5 positioned in back of the set of rear wheels 35 I2. Theirear and auxiliary wheels are each provided with the usual brakes l1 and I8, respectively. The sets of rear wheels l2 and auxiliary wheels i5 form part of a carriage C which is arranged to pivot on a transverse axis 40 relative to the other part of the chassis.

The carriage C includes two relatively movable frames 2'I' and 28'. The frame 21 comprises a yoke 88' and a platform II. The arms of the yoke 88' are pivotally connected to the 45 rear vehicle springs 82' at 88'. The housing 85' for the axle for the rear wheels i2 is secured in any suitable manner to the ends of the arms of the yoke 88'. The platform 8| extends rearwardly from the yoke 88' in a substantially horizontal plane and comprises a pair of spaced longitudinal frame members 86'. The forward ends of the members 86' are connected by the V- shaped portion 88' of the .yoke 88' having a horizontal slot 81. The rear ends of the members 65 88' are connected by a cross member 88' and also by a member 8' so as to provide a horizontal slot S therebetween corresponding to the slot 81'. The cross member 88' and the portion 88' of the yoke 88'. are shaped to provide bearings 60 42' and 48' respectively.

The frame 28' comprises a plate or red 45' extending between and slidably movable in the slots 81' and 8 both longitudinally and transversely of the vehicle chassis. The housing 46' for the axle for the auxiliary wheels I5 is connected by struts 41' which are provided with bearings 5 which surround and rotatably engage cylindrical portions of the rod 45'. A pair of pins 58' and 5| project upwardly from the top surface of the platform 45' and are spaced apart a greater distance than the bearings 42' and 43'. The pin BI is spaced a substantially greater distance from the axle for the auxiliary wheels l5 than is the pin 58'. The pins 58' and SI 78 are adapted to rotatably engage the bearings 43' and 42 respectively, the pin 50 being out of engagement with the bearing 43' when the pin 5| is in engagement with the bearing 42' and vice versa. Separate leaf springs 52' are suitably secured to each of the frame members 36' so that their free ends are adapted to engage opposite longitudinal edges of the platform 45' and abut an enlargement 55' formed thereon.

Preferably, the pivotal connections 33 between the carriage C and the springs 32' are positioned nearer to the axle for the rear wheels l2 than to the axle for the auxiliary wheels l5 so that a greater proportion of the load carried upon the vehicle chassis is supported by the rear wheels l2 rather than by the auxiliary wheels l5.

The operation of this structure is similar. to that illustrated in Figs. 1 to 4. The important difference between the structure shown in Fig. 5 and that shown in Figs. 1 to 4 is that in the latter the pins 50 and 5| are spaced substantially equidistant from the axle for the auxiliary wheels, whereas in the structure shown in Fig. 5 the pin 5| is spaced a substantially greater distance from the axle for the auxiliary wheels l5 than is the pin 50'. This makes it possible to reverse the position of the frame 28' in the carriage C as is illustrated in Fig. 6 so that the pin 50' is adapted to engage the bearing 42' while the pin 51' is adapted to engage the bearing 43'. By changing the position of the frame 28' from that as shown in Fig. 5 to that as shown in Fig. 6, the axle for the auxiliary wheels [5' is brought closer to the axle for the rear wheels I2 which is of advantage if it is desired to transfer the carriage C to a shorter truck chassis. This, of course, concentrates the weight of the load upon the vehicle at points closer together upon the roadway. It will be understood, however, that even when the carriage C is to be used on a short truck chassis,

the frames 21' and 28' may bear the relationship shown in Fig. 5 and thus distribute the weight of the load upon the truck at points upon the roadway spaced farther apart. This may be of advantage where the truck is to carry 'an excess load and is to be driven over roadways which are apt to be injured by the concentration of heavy loads thereupon.

In certain cases it may be desirable to posi: tion the rear driving wheels l2 in back of the auxiliary wheels l5, particularly, where the truck is to be used under conditions where it is necessary to back up steep inclines. This may be brought about easily by reversing the carriage C so that the rear wheels 12' are in back of the auxiliary wheels I 5'. Fig. 7 illustrates the construction when the carriage C has been reversed from the position shown in Fig. 5. Fig. 8 illustrates the construction when the carriage C is reversed from the position shown in Fig. 6.

I claim:

1. In an automotive vehicle having an auxiliary set of wheels and a set of rear wheels, a pair of frames one of which is movable relative to the other longitudinally of the vehicle between two positions, said rear wheels being mounted upon one of said. frames and said auxiliary wheels being mounted upon the other of said frames, and means upon said frames adapted to cooperate to permit said auxiliary wheels to swing about a point in front of said auxiliary wheels when said movable frame is in one of said positions and adapted to cooperate to permit said auxiliary wheels to swing about a point in back of said wheels when said movable frame is in the other of said positions. 4

2. In an automotive vehicle having an auxiliary set of wheels and a set of rear wheels, a pivotally mounted carriage having a pair of frames one of which is movable relative to the other longitudinally of the vehicle between two positions, said rear wheels being mounted upon one of said frames and said auxiliary wheels being mounted upon the other of said frames, means upon said frames adapted to cooperate to permit said auxiliary wheels to swing about a point in front of said auxiliary wheels when said movable frame is in one of said positions and adapted to cooperate to permit said auxiliary wheels to swing about a point in back of said wheels when said movable frame is in the other of said positions.

3. In an automotive vehicle having an auxiliary set of wheels and a set of rear wheels, a pivotally mounted carriage having a pair of frames one of which is movable relative to the other longitudinally of the vehicle between two positions, said rear wheels being mounted upon one of said frames and said auxiliary wheels being mounted upon the other of said frames, means 'upon said frames adapted to cooperate to permit said auxiliary wheels to swing about a point in front of said auxiliary wheels when said movable frame is in one of said positions, and adapted to cooperate to permit said auxiliary wheels to swing about a point in back of said wheels when said movable frame is in the other of said positions, the pivotal mounting for said carriage being spaced a greater distance from the wheels carried by said movable frame than from the other set of wheels. I

4. In an automotive vehicle having an auxiliary set of wheels and a set of rear wheels, a pair of frames one of which is movable relative to the other longitudinally of the vehicle between two positions, one of said sets of wheels being mounted upon said movable frame, means upon said frames adapted to cooperate to permit said auxiliary wheels to swing about a point in front of said auxiliary wheels when said movable frame is in one of said positions, and means upon said frames adapted to cooperate to permit said auxiliary wheels to swing about a point in back of said wheels when said movable frame is in the other of said positions.

5. In an automotive vehicle having an auxiliary set of wheels and a set of rear wheels, a pair of frames one of which is movable relative to the other longitudinally of the vehicle between two positions, one of said sets of wheels being mounted upon said movable frame, a pair of spaced studs carried by the last mentioned frame, the other of said frames having a pair of bearings spaced apart a. distance less than the distance between said studs, one of said bearings being positioned in front and the other in back of said auxiliary wheels whereby one of said studs may rotatably engage one of said bearings when said movable frame is in one of said positions and the other of said studs may rotatably engage the other of said bearings when said movable frame is in the other of said positions.

6. In an automotive vehicle having an auxiliary set of wheels and a set of rear wheels, a pair of frames one of which is movable relative to the other longitudinally of the vehicle between two positions, one of said sets of wheels being mounted upon said movable frame, means upon said frames adapted to cooperate to permit said auxiliary wheels to swing about a point in front of 75 said auxiliary wheels when said movable frame is in one of said positions, means upon said frames adapted to cooperate to permit said auxiliary wheels to swing about a point in back of said wheels when said movable frame is in the otherof said positions, and resilient means interposed between said frames tending to resist relative movement thereof. k

7. In an automotive vehicle having an auxiliary set of wheels and a set of rear wheels, is pivotally mounted carriage having a pair of frames one of which is movable relative'to' the other longitudinally of the vehicle between two positions, one of said sets of wheels being mounted upon said movable frame, a pair of spaced studs carried by the last mentioned frame, the other of said frames having a pair of bearings spaced apart a distance less than the distance between said studs, one of said bearings being positioned in front and the other in back of, said auxiliary wheels whereby one of said studs may rotatably engage one of said bearings when said movable frame is in 'one of said positions and the other of said studs may rotatably engage the other of said Y bearings when said n iovable frame is in the other of said positions.

8. In an automotive vehicle having an auxiliary set of wheels and a set of rear wheels, a pivotally mounted carriagehaving a pair of frames one of which is movable relative to the other longitudinally of the vehicle between two positions, one of said sets of wheels being mounted upon said .movable frame, a pair of spaced studs carried by the last mentioned frame, the other of said frames having a pair of bearings spaced apart a distance less than the distance between said studs, one of said bearings being positioned in front and the other in back of said auxiliary wheels whereby one of said studs may rotatably engage one of said bearings when said movable frame is in one of said positions and the other of said studs may rotatably engage the other of said bearings when said movable frame is in the other of said positions, the pivotal mounting for said carriage being spaced a greater distance from the wheels carried by said movable frame than from the other set of wheels.

9. In an automotive vehicle having an auxiliary set of wheels and a of rear wheels, means per-v mitting said auxiliary wheels to swing about a pivot in front of said auxiliary wheels when the vehicle is moving forward and about another pivot in the rear of. said auxiliary wheels when the vehicle is moving rearward comprising a pair of frames one of which is movable relative to the other longitudinally of the vehicle between two positions, one of said sets of wheels being mountstuds carried by one of said frames, the other of said frames having a pair of bearings spaced apart a distance different than the distance between said studs, said pairs of bearings and studs being arranged so that one stud may rotatably engage one of said bearings when said movable one of said frames and said auxiliary wheels being mounted upon the other of said frames, and means upon said frames adapted to cooperate to permit said auxiliary wheels to swing about a point in front of said auxiliary wheels when said movable frame is in one of said positions and adapted to cooperate to permit said auxiliary wheels to swing about a point in back of said wheels when said movable frame is in the other of said positions, said means being arranged with respect to said auxiliary wheels so that one of said points about which said auxiliary wheels may swing is closer to the axle for said auxiliary wheels than is the other of said points.

HENRY PINARD.

ed upon said movable frame, a pair of spaced 

